Hang on, now I think I know what is wrong.
Dorico 6 and also the audio engine are not WoA native. Instead the Intel architecture code gets executed in emulation mode, and so also all plug-ins need to be compiled for Intel architecture. But your HALion Sonic and Groove Agent are the versions compiled for ARM. Then the vstscanner runs in emulation mode and puts them on the blocklist because of wrong architecture.
Now, what you need to install then are the Intel versions of HALion Sonic and Groove Agent SE.
Does that make sense to you?